The DeleteUrlCacheGroups subroutine enumerates the cache groups that exist in the WinInet cache database. The script then gathers information (e.g., how much disk space the group consumes) about each cache group, as the code excerpt in Listing 4 shows. Notice that the block of code at callout A in Listing 4 uses a trick to assign an array of values to a hash. This trick works because the order of the array is well known. However, the block would cause errors if the code didn't disable the use of strict for that block. The code excerpt that Listing 5 shows deletes and clears the cache (assuming you've directed the script to do so, as I explain later).
The DeleteUrlCacheFiles subroutine does essentially the same thing as the DeleteUrlCacheGroups subroutine but deletes individual cache entries as opposed to a cache group and is much more complicated than the DeleteUrlCacheGroups subroutine. Each cached entry contains information and attributes such as the date and time when the file was cached, the URL that maps to the entry, and the cached file's expiration time. Each cached entry can be a different size, so the script first allocates a 1KB buffer to the $pCacheInfo variable. The code excerpt that Listing 6 shows begins the enumeration process but must determine whether the buffer is large enough to hold the cache entry data. If the buffer in insufficient, the script reallocates the buffer. The script uses this strategy each time it accesses a cache entry. The code excerpt that Listing 7 shows uses the same technique as the code in Listing 4 to unpack the cached entry data into a %Cache hash. After extracting the cache data, the script determines the cache entry type (i.e., a cookie, URL history entry, or cached file). . . .
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